Need Load Data For Short Barrel 308

[303 hunter]

I recently bought a Ruger Gunsite Scout with a 16.5" barrel, and I'd like some load data from those of you who who've loaded 308 for a similar barrel length. I've got Varget, CFE 223, H335, and H322 powder, CCI 200 and 250 primers, Hornady 150 SST bullets, and once fired PPU brass.

I'm thinking that a faster burning powder would be beneficial in the shorter barrel, but I'm not sure which ones would would work. What do you load in a short barrel 308? Thanks!

 

[macgrumpy]

I shoot a M1A SOCOM with a 16 1/4" barrel, the best powders I've found for the 150gr and heavier bullets have been IMR 3031 and IMR 4166.

 

[ArchAngelCD]

IMO there is no reason to change powders, especially if you have several good .308 loads already worked up. If it were that important the commercial loaders would be marketing special ammo for scout rifles and I don't know of any.

 

[macgrumpy]

Actually the commercial market does make a special cartridge designed for 16" barreled .308/ 7.62x51mm rifles, it's made by Federal and they call it their T762TNB1 ammo. This ammunition is a copy of the military's MK319 Mod 0 cartridge which was developed for the SCAR 17 rifle. The standard model of the SCAR uses a 16" barrel and the ammo was developed by ATK (parent company of Federal Cartridge) to be optimized for that length barrel.

 

[RPRNY]

Interesting issue. I have experience of the same investigations with an 18" M49 Persian Mauser sporter in 8 x57. I too thought, shorter barrel, different powders. And when advised that a good load in a 22" barrel would likely be a good load in an 18" barrel, just a little bit slower, I scoffed at the ignorance that comment obviously demonstrated.

After much experimentation with different powders, I was forced to admit my own ignorance for not having listened to the wisdom of others. It turned out that my best results were with classic loads from Ken Waters that had worked well with his full length rifle. I did find a good load with IMR 8208 XBR via the experimentation, but it was not substantially better than old standbys like 4064.

The one matter in which you may wish to experiment given your very short barrel is diminishing the fireball. In this, the 8208 XBR load was better, diminishing the nuclear fireball to a mere blinding flash.

FWIW, 44 grs of 4064 under 147 grs FMJ has been an excellent load in my 18" PTR91 308/7.62x51

 

[macgrumpy]

While I like the IMR powders that I mentioned those powders worked best with the heavier bullets, for the 130 gr MK319 Mod 0 ammo they used a ball powder of some kind. I did have good luck with IMR 3031 with the 110gr Vmax) and heavier bullets up to 168gr.

 

[macgrumpy]

You will find that in the .308 there is a big difference between what works well in a 16" barrel as opposed to longer lengths, that 16" is sort of a tipping point. I've done a lot of work, along with a couple of other people, on barrel lengths of 16 1/4", 18", and 22" using .308 Winchester cartridges. We found that one of the best advantages to buying a Springfield M1A Scout was that the same ammo that worked well in the full sized 22" barreled rifles worked well with the 18" barreled Scout rifle but to get the same kind of accuracy out of the 16 1/4" SOCOM you needed to load your own or stick with light commercial ammo (the lighter ammo produces higher velocities which pushes the bullet to a more reasonable speed in the shorter barrel).

The difference in the velocity developed by the 16" barrel is just enough to cause the standard commercial ammo to be outside it's best performance envelope and accuracy just suddenly becomes drastically poorer. If you choose a commercial .308 cartridge that was developed for a typical hunting rifle it will probably group pretty well in a barrel length of 22 to 24 inches but in a 16 inch barrel you'll see a pretty poor result.

 

[ants]

308 Win and/or 7.62x51: I load for an AR-10 16" and several bolt actions of 22 and 24 inch. I use the same loads for all 3 guns and all work very well. It would be fun to speculate otherwise, but my best loads (with R-15 and Varget) work in all guns except the short AR-10 gives up a hundred fifty feet per second. That slows it down over long distance.

Your bullet choice is good, I happen to find better performance with 168 grain but it's a personal choice. I favor Nosler and Barnes lineup, and the Hybrids from Berger.

In gas-operated semiautomatic rifles, you might need special loads if the short barrel has a shortened gas system, thus the special ammo for short barrels. For your bolt Ruger, it won't make a difference.

Your powder choice: I can't vouch for CFE223 in 308, I haven't used it. I strongly recommend your Varget and H335. H322 is OK but just OK. The usual R-15 and 4064 and 4895 and 4350 still work well, if you have them you might try some tests.

Primer: Unless you have inconsistent ignition (inconsistent velocity and/or accuracy) you won't need magnum primers unless your weather is very sub-freezing, but keep them on hand because sometimes it helps. You never know.

Good luck with your new rifle!

 

[macgrumpy]

Yup, it's obvious to me that quite a few people find it fun to speculate. I suspect that how you define what works well is relative. I'm sure that the conflicting expert advice that the OP has received has done absolutely nothing to help find a good powder so good luck.

 

[redbullitt]

I was hoping for actual short barrel lengths lol... 16 inch, or in your case 16.5 is no problem at all. Personally I use the same powder, varget, in my 16 inch 308 and 26 inch 308.I will say that the ar10 is a different animal and DOES have different needs.

No complaints, just a bit lower velocity from the shorter tube. They say the best powder tends to be the best regardless of barrel length, though semi autos can be different. Accuracy and precision are great with both, though the shorter barrel seems to be notably more blasty... as expected.

I am using a Desert tech rifle, with a 16 inch 22 inch and a 26 inch barrel for my comparison. Everything is the same for the comparison except the barrel.The shorter barrel generally runs a little under 2500 fps, and the longer one is closer to 2700 fps. Same loading for simplicity sake. 178 amax and varget at standard coal. Load is not hot and brass life is excellent. Both barrels are better than .5 moa with me shooting this load when I have been practicing as I should, so clearly I am the limiting factor here. They shoot just as well out to about 700 yards, the longest shot I have easy access to. I can also add a 16.5 inch GSR in 308, a UGSW 308 18 inch barrel, a GAP Hospitaller in 308 with a 22 inch tube. They get pretty much the same loading with the SAME powder regardless of barrel length. Minor tweaks between all of them in COAL etc, but they DO shoot as well as I ask them to with the same powder. I am not a bench rest shooter, rather a precision/practical oriented type of guy. Maybe that extra .01 can be shaved off my group, but to be honest I like shooting more than loading, and once I find a loading that works how I need I shoot it.

I frequently shoot my GSR, as it is my hunting rifle, so hopefully I can help. It likes a wide range of bullets and powders. Mine is not picky at all. I load to standard length with a charge of Varget. CFE223 is excellent as well and tends to offer a bit more speed, but I am much better stocked on varget and do not want to add another powder. 43g of varget and a 175 SMK or 178 amax runs just about 2475 from my rifle with Fed brass. Velocity is obtained with a Oehler 35p that is known to be reliable. Accuracy is easily sub MOA with minimal load development and no fancy loading practices. I have taken deer out to 350 yards with this rifle/loading, and steel torso targets are not problem out to my longest shot here at about 700 yards.

Start under any loading you want to explore and figure out for your rifle of course, as yours most assuredly is not the same as mine.
Not sure if you are into it, but my GSR shoots VERY well with cast bullets, 160s @1850fps. Bullet is a ranch dog flat nose GC. Probably one of the best and easiest cast bullet rifles I have gotten to play with.

All that said, I think it may be possible some powders can be better suited for short barrels, but without much experimentation I am not sure how noticeable it is. In the 308 application I am after precision with ENOUGH velocity, not chasing rockets, so I have typically not found a reason to switch powders based on barrel length. I would not be opposed to trying other powders based on barrel length, but I have never seen the need. The only caveat there would be with actual SBR lengths or semi auto rifles. As to blast difference between powders in a rifle, suppressor and/or ear plugs make that a moot point.

SOOO, for all practical purposes I think you would be quite happy with a charge of varget whether your barrel is 16 inches or 26 inches!

 

[RPRNY]

Yup, it's obvious to me that quite a few people find it fun to speculate. I suspect that how you define what works well is relative. I'm sure that the conflicting expert advice that the OP has received has done absolutely nothing to help find a good powder so good luck.

I can see how you arrived at your user name.

 

[303 hunter]

-PPU brass
-46 gr Varget
-150 SST
-CCI 250 primer
-2.80 OAL

This was the most accurate load in a ladder I worked up this morning. 5 rounds went into a cloverleaf at 100 yards, and averaged 2660 fps. I'm pretty happy with this load, but I'll play with OAL to see if I can do better.